1. Field of the Invention
The present invention relates to a system furnished with a plurality of memory devices, and particularly to a data transfer technique for the same.
2. Description of the Related Art
An inkjet printer, which is one example of liquid ejecting apparatus, typically has one or more installed ink receptacles provided as detachable liquid receptacles. Some ink receptacles are furnished with memory devices. The memory device stores information of various kinds, for example, the remaining ink level or the color of the ink in the ink receptacle (see JP 2002-370383 A, JP 2004-299405 A). A control unit provided to the printer communicates with the memory devices of the ink receptacles.
However, in conventional techniques, insufficient consideration is given to the issue of dependability of communication between the control unit provided to the printer and the memory devices provided to the ink receptacles. For example, there is a risk that, for reasons such as faulty contact between the electrical contact portions of the printer and an ink receptacle, communication faults may occur between the control unit provided to the printer and the memory device of the ink receptacle. If operation of the print control unit is continued on with the communication fault unresolved, there is a risk of problems such as errors arising in the memory contents of the memory device.
In general, it is preferable for data transfer speeds to be as fast as possible. For example, it is possible to boost data transfer speeds by increasing the clock frequency for data transfers. However, if the clock frequency is too high, the problem of excessively high flow of consumption current through data lines may arise. In the past however, sufficient attention is not paid to the issue of the consumption current needed for communication or data transfer between a control unit and memory devices. If the consumption current needed for data transfer between a control unit and memory devices is reduced, the current capacity of the data transfer circuitry may be reduced as well, thereby affording the advantages of simpler circuit design, as well as lower likelihood of heat emission or noise problems. However, conventional techniques did not demonstrate much innovation in this regard.
Moreover, this issue is not limited to printers, but is rather an issue common to all manner systems having a plurality of memory devices.